Hypodermic syringe barrel assembly



Sept. 25, 1962 E. 0. ECKHART HYPODERMIC SYRINGE BARREL ASSEMBLY .u y 2 r 5 a p w a WM. w m 2 x Z 3 m -11.... 'JIIJIIIIIIIPHL: Z flu. B M 1 1 K r 2 Filed NOV. 18, 1959 Sept. 25, 1962 E. o. ECKHART HYPODERMIC ssmzmcm BARREL ASSEMBLY 2 Sheets-Sheet 2 Filed Nov. 18, 1959 IN V EN TOR. 696/9)? 0. ECAHART nited States This invention relates to a structurally and functionally improved hypodermic syringe barrel assembly, and also teaches a novel method of producing that assembly.

By means of the present invention, a hypodermic syringe is produced which may be heat sterilized at 400 F. without developing leaks and without damage resulting to its parts.

Moreover, a syringe assembly will be provided in which the danger of breakage in ordinary handling will be materially reduced, and in which the cost of manufacture will be minimized.

With these and other objects in mind, reference is had to the attached sheets of drawings illustrating a practical embodiment of the invention, and in which:

FIG. 1 is a perspective view of a complete syringe barrel assembly;

FIG. 2 is a fragmentary enlarged sectional view thereof taken along the line 22 in the direction of the arrows, as indicated in FIG. 1;

FIG. 3 is also an enlarged sectional side view showing a preferred form of tip fitting conveniently included in the assembly; and

FIGS. 4, 5 and 6 are somewhat diagrammatic and partially sectional side views illustrative of successive steps in the manufacture of the assembly.

Referring primarily to FIG. 1, the numeral 10 indicates the barrel of a hypodermic syringe, which at its open end may present a flange 11 of suitable configuration. This syringe, in accordance with conventional practice, is formed of glass. At its opposite end it carries a metallic fitting 12, which, as shown, is of the Luer type. Alternatively, fittings of other types might be employed.

Referring to FIG. 2, it will be seen that the upper end of the barrel assembly is defined by an integral tip portion 13. Adjacent the base of this portion, a recess in the form of an annular groove 14 exists. Portion 13 terminates in an outer face 15; a chamfered surface 16 intervening this outer surface and the side wall of portion 13. Communication between the interior of barrel 10 and outer surface 15 is established by a bore 17. Contrary to accepted technique, the side face or faces of tip portion 13 are not ground. Thus, the hard skin surface remaining after formation of the barrel is maintained.

In FIGS. 2 and 3, the detailed structure of a preferred form of end fitting has been illustrated. As will be understood, if such fitting embodies the Luer design, it will include a collar portion 17' having a double thread 18 which is spirally disposed and engages in the usual manner with the projecting portions of a needle hub. In any event, this fitting is made of metal and includes a side Wall 19 defining a socket portion. The outer edge zone of the latter is countersunk or beveled, as indicated at 20. Extending outwardly from the base surface of the socket and forming a part of that surface is a flange 21, which has a diameter slightly in excess of that of the bore 17. concentrically disposed with respect to annular flange 21, and also forming a part of the base surface, is a second flange or projecting portion 22. The character of the metal providing this end fitting and the thickness of flange 21 are such that in response to a thrust of reasonable force against that flange, it will distort. The outer edge zone of flange or atent 3,055,363 Patented Sept. 25, 1962 ice projection 22 is inwardly of that of flange 21. Also, the mass of this portion is greater than the thickness of the walls defining flange 21. The space embraced by the latter is coextensive with the bore 23 of a tip 24 forming an integral part of the fitting. As will be understood, this tip extends into the hub portion of a needle mounted on the fitting and establishes a leakproof connection with the surface thereof.

At this time it is to be observed that the bore of the socket of fitting 12 is of constant diameter. The same is true of the outer face of tip portion 13. Considering an assembly of one size, this unground glass tip portion would measure 0.3446" plus .003" minus .000". The base of groove 14 would measure 0.300" in diameter. The area or Width of the beveled or chamfered surface 16 would be .032. It would extend conveniently at a 45 degree angle and define at the outer face of the tip portion a diameter of 0.300". The fitting, as in FIG. 3, would include a socket or recess having a diameter of 0.342", plus .0016", minus .000". The countersunk or beveled surface 20 would preferably extend at a 30 degree angle and have an area of .032". Its maximum diameter would preferably be around 0.390. The metal fitting or tip assembly, after it has been produced, is stress-relieved at 570 F. for a period of approximately one-half hour. Following this, the fitting is plated.

Under all conditions, tip portion 13 will involve a diameter in excess of the initial diameter of the socket embraced in the fitting. Surfaces 16 and 20, however, will define what might be termed overlapping diameters. Accordingly, these surfaces may be interengaged to dispose tip portion 13 so that its outer surface extends into the socket. With the parts thus arranged, and a thrust being exerted, surfaces 16 and 20 will cooperate to guide the tip portion 13 into the socket, while a camming action is simultaneously exerted on the parts.

A mechanism suitable for assembling the parts has been shown somewhat diagrammatically in FIGS. 4, 5 and 6. In those views the numerals 23' indicate supporting and guiding surfaces with which mounting members 24 are operatively associated. These members carry mandrels 25 upon their upper faces. In turn extending beyond these mandrels are pins 26. The diameter of the mandrels is such that they may be received within the bores of the syringe barrels. The diameter of pins 26 is sufliciently small so that they may be passed through bores 17 of tip portions 13 and bores 23 of the fittings. The length of the pins is sufliciently great so that they may simultaneously extend into these bores to maintain the parts in operative association.

Thus, as in FIG. 4, a barrel is ensleeved over the mandrel, and pin 26 passes through and beyond bore surface 17. Thereupon, and preferably by suitable mechanism (not shown), the fitting 12 is axially aligned with tip portion 13 and moved toward the same so that pin 26 enters bore 23. This condition of the parts has been illustrated in FIG. 5, wherein there has also been shown the initial telescopic relationship of the fitting with respect to the tip portion of the barrel. At a further station (FIG. 6) a raising mechanism 27 is present which will elevate supports 24' together with the mandrels and parts carried thereby. In line with this station, a stop member 28 is positioned. This stop member conveniently cooperates with the outer edge of collar 17, if the latter forms a part of the fitting. Otherwise, it may be engaged by any other suitable portion of that fitting.

After the assembly shifts to the station shown in FIG. 6, the raising mechanism or plunger 27 elevates the mandrel with the syringe barrel and the fitting loosely supported upon the latter. As that fitting engages stop member 28, it will have its axis in perfect alignment with the barrel axis. Thrust is exerted which results in telescopic movement of the fitting over the tip portion, and the fitting is subjected to radial tension. Axial motion of the parts is continued beyond a point at which the outer face of the tip portion engages the edge of flange 21. In the initial stages of this thrust action, surfaces 16 and 20 will cooperate and cam against one another to assure a proper guiding of the tip portion with respect to the fitting and an ensleevement by the latter of the tip portion.

With the end surface of the tip portion engaging the edge of flange 21 and movements of the parts continuing, that flange will be distorted and bowed in the manner shown in FIG. 2. A seal will be established which will assure against leakage of liquid, without it being necessary to employ a washer or similar structure. The edge of flange or raised portion 22 will also be brought into intimate contact with this outer surface and will sealing'ly engage the same.

As the parts are positioned in this manner, the outer edge zone of the fitting socket overlaps the recess or groove 14. Under these conditions, this zone may be crimped or spun inwardly, as shown at 29 in FIG. 2, so that it extends into the recess or groove of the barrel to thus retain the fitting against axial movement in a direction outwardly with respect to the barrel. To achieve this result, and as indicated at 30 in FIG. 6, one or more spinning wheels may be positioned adjacent stop 28. These wheels move inwardly in line with the zone of groove 14 after the parts have been properly positioned, and serve to crimp or shift the edge zone of wall 19 inwardly, as indicated.

As will be understood from the foregoing, a syringe barrel assembly embodying the present teachings may readily be subjected to heat sterilization with no leaks resulting. This will be true even when the parts are subjected to 400 F. of dry heat. These results obtain due to the stress-relieving which is resorted to, as Well as the securing of the parts by the spinning or crimping operation after they have assumed proper relative positions. It will be appreciated that stress-relieving reduces the tendency of the metal fitting to crack or split when subjected to temperature changes. The fitting will remain permanently in place. No sealing washer or functionally equivalent structure is employed, so that costs are reduced; the assembly being free from leakage. Also, costs are reduced in manufacture because no grinding of the glass tip portion occurs. Therefore, the skin surface of the glass remains intact, and the tip portion is not likely to fail when subjected to lateral stresses. It is apparent that high speed assembly is achieved by the procedure herein described.

Thus, among others, the several objects of the invention as specifically aforenoted are achieved. It is apparent that numerous changes in construction and variations in the steps of the method might be resorted to without departing from the spirit of the invention as defined by the claims.

I claim:

1. A syringe assembly including in combination a barrel end portion having an outer face and formed with a bore, a metallic fitting having a socket part, a tip projecting outwardly from the base of such socket part and also formed with a bore extending through to that base surface, a first flange extending inwardly of such socket part from the base surface and providing an extension of the tip bore, and a second flange also extending inwardly from such socket part and concentrically disposed with respect to said first flange, said second flange having initially less height than such first flange, said socket enclosing the end portion of the barrel, both flanges having their edges in direct contact with the outer face of said end portion and said first flange being deformed to present a height substantially equal to that of the second flange.

2. In an assembly as defined in claim 1, the mass of the second flange being greater than that of the first flange and said second flange being substantially free from deformation.

3. In an assembly as defined in claim 1, the edge zone of the socket part being beveled and the end portion of said barrel being chamfered to guidingly contact the beveled surface and establish a telescopic relationship between said end portion and socket part.

References Cited in the file of this patent UNITED STATES PATENTS 1,457,781 Loughead June 5, 1923 1,774,983 Loughead Sept. 2, 1930 2,217,602 Smith Oct. 8, 1940 2,767,710 Blackman Oct. 23, 1956 2,811,155 Dunnican Oct. 29, 1957 2,855,927 Henderson Oct. 14, 1958 

